1. Field of the Invention
Embodiments of the invention relate to a liquid crystal display device, and more particularly, to a liquid crystal display device and the method of driving the same. Although embodiments of the invention are suitable for a wide scope of applications, they are particularly suitable for obtaining a liquid crystal display device including an image sensor and the method of driving the same.
2. Discussion of the Related Art
Liquid crystal display (LCD) devices use the optical anisotropy and polarization properties of liquid crystal molecules to produce an image. The liquid crystal molecules have long and thin shapes, and have the optical anisotropy property, such that the liquid crystal molecules can be aligned along an alignment direction. The liquid crystal molecules also have the polarization property, such that the alignment direction can be changed according to an intensity of an applied electric field. In particular, the arrangement of the liquid crystal molecules can be changed by varying the intensity of the electric field. Consequently, light transmittance of the liquid crystal molecules is controlled by the electric field, and the LCD device displays images due to the changes in light transmittance.
In general, an LCD device includes a liquid crystal panel and a driving circuit. The liquid crystal panel includes first and second substrates spaced apart from each other and a liquid crystal layer between the first and second substrates. The first substrate, which is commonly referred to as an array substrate, has a thin film transistor and a pixel electrode, and the second substrate, which is commonly referred to as a color filter substrate, has a color filter layer and a common electrode. The driving circuit electrically drives the liquid crystal panel. Since the LCD device is a non-emissive type device, the LCD device includes a light source, such as a backlight unit, under the liquid crystal panel.
FIG. 1 is a schematic diagram illustrating an LCD device according to the related art. In FIG. 1, an LCD device includes a liquid crystal panel 10, a gate driver 20, a data driver 40, a timing controller 60 and a backlight unit 80. The liquid crystal panel 10 includes a plurality of gate lines GL1 to GLn and a plurality of data lines DL1 to DLm on a substrate. The plurality of gate lines GL1 to GLn cross the plurality of data lines DL1 to DLm to define a plurality of pixel regions. Each of the pixel regions includes a thin film transistor TFT and a liquid crystal capacitor Clc to display images. The gate driver 20 and the data driver 40 supply driving signals and image signals to the liquid crystal panel 10 through the plurality of gate lines GL1 to GLn and the plurality of data lines DL1 to DLm, and the timing controller 60 controls the gate driver 20 and the data driver 40. The backlight unit 80 is disposed under the liquid crystal panel 10 and supplies light onto the liquid crystal panel 10.
A thin film transistor has been explored for applications as a switching element and also as an image sensing element. The thin film transistor, when functioning as an image sensing element, stores information corresponding to intensity of light and outputs the stored information in response to an external control signal. For example, the thin film transistor, when functioning as an image sensing element, may be used as an image reader of an image treating machine, such as a scanner and a digital duplicator.
Recently, a multi-functional electronic device has been the subject of research and development so that instead of using several traditional goods, a single device can achieve the same results. In addition, a device including an image sensing element is required to have various functions.
Accordingly, an LCD device including an image sensor has been researched and developed. Since an LCD device including an image sensor displays and senses images, such an LCD device including an image sensor has advantages in space utilization and production cost. In an LCD device including an image sensor, however, since a selected pixel receives a sensed data corresponding to an adjacent pixel due to light scattering, a sensed data corresponding to the selected pixel may be interfered.